userenv 1054

I recieve this error numerous times in a windows 2003 mixed domain on all of
my XP clients. THere are no errors on any of the DC's.
It seems my group policies all run as expected except for logon scripts. If
the computer is restarted and logged onto EVERY policy and setting is
applied. However the next day, when the user logs on their login script does
not run and event 1054 is noted multiple times from throughout the night. At
that point I confirm sysvol connectivity and there are no errors with a
gpupdate command.
I've not tried this as my userenv.log file denoted a fast link at every
instance:
USERENV(29c.a10) 15:46:35:510 PingComputer: Fast link. Exiting.

I've also added the GpNetworkStartTimeoutPolicyValue and tried various
settings as described in KB840669
as well as tried disabling Media Sense as noted in kb326152.
Any help or suggestions would be greatly appreciated.
Thanks,
Tom